A number without denominator such is equal to number with denominator 1.
So, 24 is equal to 24/1
5/8 x 24
= 5/8 x 24/1
= (5x24) / (8x1)
= 120/8
= 15
Using cross multiplication

(x-4)(x+2)=0
x-4=0
x+2=0
Thus x=4,-2
Equal is the with the 38+
3x3x3x3 = 81
x.x.x.x = x^4
2x2x2x2 = 16
B. 81x^4/16